1. Field of the Invention
The present invention relates to a transmittance adjusting device, an observation apparatus and an observation system, which adjust light with specific wavelengths to enhance contrast for observation of an object in the inside of a body.
2. Description of the Related Art
Endoscope apparatuses enabling, e.g., inspection of the inside of an organ, identification or treatment of an affected site by means of insertion into a body cavity of a patient without dissection have widely been used.
For such endoscope apparatuses, while ones that display a color observation image of the inside of a subject on a monitor using white color illuminating light close to natural light for normal observation have generally been used, in recent years, endoscope systems enabling narrow band imaging (NBI) in which light with two specific wavelengths is irradiated have been disclosed for example, in Japanese Patent Application Laid-Open Publication No. 2007-289278, the endoscope systems enabling observation with improved contrast of, e.g., blood vessels near the superficial portion of the mucous membrane of the inner wall of a body cavity to easily determine an affected region.
In contrast to the endoscope system disclosed in Japanese Patent Application Laid-Open Publication No. 2007-289278, for example, Japanese Patent Application Laid-Open Publication No. 2003-93343 discloses a technique in which an endoscope apparatus is provided with a red-color component cut filter that eliminates components with wavelengths causing deterioration of contrast of, e.g., the mucous membrane and blood vessels in the inside of a body cavity (long wavelengths) to ensure minimization of red-color components in a color image, enabling enhanced display of contrast between the mucous membrane and the blood vessels, and the other tissues.
Furthermore, for example, Japanese Patent Application Laid-Open Publication No. 2003-102684 discloses a technique in which an electronic endoscope apparatus is provided with a wavelength calibration filter that cuts off light with wavelengths of red-color components as long as such cutoff does not impair the color image, suppressing occurrence of halation, because mucous membranes in a living body largely reflect such light with red-color components.